Scrubbing machine



Feb- 2 5 1964 J. 1 .BURGooN 3,121,895

scRUBBING MACHINE INVENTOR. JACK I.. BuRGooN ATTORNEYS Feb. 25, 1964 J. L. BURGOON SCRUBBING MACHINE Filed Jan. 8, 1962 5 Sheets-Sheet 2 INVENTOR JACK L. BURGOON MMM Feb. 25, 1964 J. L. BuRGooN 3,121,895

scRUBBING MACHINE Filed Jan. 8,*1962 5 Sheets-Sheet 3 INVENTOR.

2F17 y ZZ JACK L.. BuRGooN AT TOR NEYS United States Patent C) 3,121,895 SCRUBEING MACHINE Jack L. Burgoon, Toledo, Qhio, assigner to American Lincoln Corporation, Toledo, Ghio, a corporation of Qhio Filed Jan. 3, 1952, Ser. No. 164,750 11 Claims. (Cl. 15-50) ri`his invention relates to an improved scrubbing machine for cleaning lage surfaces.

The new scrubbing machine has a plurality of small scrubbing heads in place of the ustul one or two large ones, the smaller heads enabling the new machine to cover as wide a path as conventional ones but with a substantially smaller horsepower requirement. This is achieved in the new machine because the plurality of small scrubbing heads actually contact a much smaller area of the surface with the result that considerably less power is required to drive them. The small scrubbing heads are staggered in a direction generally perpendicular to the direction of movement of the machine and also overlap slightly to provide an etfective scrubbing action when rotated. The scrubbing heads of the new machine are driven through sheaves which in turn are driven by a single belt connected to a motor to provide a simple, inexpensive, and trouble-free drive.

The scrubbing tools of the scrubbing heads are resiliently connected directly to driven sheaves which are rotatably mounted on central hollow axles through which water or other cleaning iluid can be supplied. The resiliency of the scrubbing tool mounting enables a more uniform load to be applied to the surface through the scrubbing tools, particularly when the surface is uneven. Further, the direct connection of the sheave and scrubbing tool saves both material and space, as will be more apparent subsequently. The central cleaning iluid supply results in more uniform cleaning and less splashing than in conventional scrubbing machines in which the cleaning fluid must be applied to the scrubbing tools eccentrically.

The scrubbing machine according to the invention also is provided with a tiltable scrubbing unit upon which the drive motor is mounted along with the scrubbing heads so that all can be lifted and lowered together, which simplies the drive connection between the motor and the scrubbing tools. rhe drive motor also is connected to the wheels of the scrubbing machine in a manner to remain engaged therewith whether the motor and scrubbing unit are raised or lowered. In addition, the drive connection between the motor and the wheels includes a novel means for engaging and disengaging the drive to the wheels.

t is, therefore, a principal object of the invention to provide an improved scrubbing machine with a plurality of small scrubbing heads.

Another object cf the invention is to provide an improved scrubbing machine with a plurality of scrubbing heads, the scrubibng tools of which are resiliently mounted directly on driven sheaves.

Still another object of the invention is to provide an improved scrubbing machine in which cleaning fluid is supplied to the center of a rotating scrubbing tool.

Still a further object of the invention is to provide a scrubbing machine with an improved drive arrangement in which a drive motor and scrubbing heads are mounted on a tiltabie scrubbing unit to move together and to provide a simpler drive connection.

Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawing, in which:

FIG. l is an overall side view in elevation of a scrub- 3,121,895 Patented Feb. 25, 194

ICC

2 hing machine embodying the principles of the invention;

FIG. 2 is a top View of a scrubbing unit of the machine shown in FIG. l;

FIG. 3 is a view in cross section, taken along the line 3-3 of FIG. 2, of a scrubbing head of the scrubbing unit;

FIG. 4 is a smaller, plan view taken along the line fi-Ji of FIG. 3 of a backing member of a scrubbing tool of the scrubbing head, with portions of fasteners assembled therewith;

FIG. 5 is a detailed view in cross section taken along the line 5 5 of FIG. 4;

FIG. 6 is a side view in elevation of the scrubbing unit shown in FIGS. l and 2;

FIG. 7 is a somewhat schematic, plan view of drive mechanism for the main wheels of the scrubbing machine;

FIG. 8 is an enlarged view in cross section taken along the line 8 3 of FIG. 7;

FIG. 9 is a View in vertical cross section of a modified scrubbing tool with modified means for mounting a scrubbing pad;

FIG. 10 is a top view of another modiiied scrubbing tool; and

FIG. ll is a view in vertical cross section of the scrubbing head of FIG. 10.

Referring to the drawings, and more particularly to FIG. 1, a scrubbing machine embodying the principles of the invention is indicated at 1() and includes a main body 12 supported on driven Wheels 14, behind Which are castors 16 which also aid in supporting the Ibody 12 and in steering the machine 1t) with the aid of a handle `18. The scrubbing machine 10 also includes a scrubbing unit 2t) mounted under the front of the machine, to which unit cleaning fluid, usually comprising water and a suitable deter-gent, is supplied, subsequently being collected by a squeegee blade 22 and picked up from the surface by a vacuum nozzle 24 located in front of the blade 22, as is known in the art. The body 12 has the usual tank for holding a supply of water for the scrubbing unit Ztl and another tank to receive dirty water picked up by the vacuum nozzle 24. A suitable tank drain 26 is provided to empty the dirty water.

In the particular embodiment shown in the drawings, the scrubbing unit 20 includes ve scrubbing heads 23 which are located in staggered relationship laterally to the direction of movement of the machine 10 with the adjacent scrubbing heads overlappingA slightly to prevent the chance that `any area of the floor will be missed. By using the ve smaller scrubbing heads 28, a path can be covered by the machine 10 which is as Wide as the path covered by a conventional machine having one or two largersorubbing heads and do so with a much smaller power requirement. By way of a specific example, the scrubbing machine 1d can cover an 18 Wide path with ve of the scrubbing heads 28 measuring approximately 3%" in diameter and driven at a speed of 600 r.p.m. by only approximately 1A horsepower. In contrast, a conventional 'scrubbing machine employing a single 18 brush to cover the same 18" Wide path is driven at approximately r.p.m. by 3A horsepower. Where the scrubbing heads 28 are electrically powered, two 12volt batteries with ratings of l00-135 ampere-hours can be used in place of four 6-volt batteries with ratings of 270-375 ampere-hours.

The scrubbing heads 28 are driven through sheaves or pulleys 3) (FIG. 3) of any suitable construction, around which sheaves extends a drive belt 32 driven by a drive `sheave 34 (FIG. 2). rPhe drive sheave 34 is mounted on a shaft 36 to which a driven motor sheave 38 is also aixed, the latter being driven through a motor belt 40 and a drive motor sheave 42 by means of a D.C.

motor 44. A resiliently-mounted idler 46 is provided to maintain proper tension on the belt 32. By wrapping the belt 32 around the adjacent sheaves 30 in opposite directions, the adjacent scrubbing heads 28 are driven in counter-rotating directions so that the adjacent portions of the adjacent scrubbing heads move in the same direction. This prevents interference should the heads contact one another and also provides a smoother ow of water on the surface being scrubbed. The belt 32 also contacts a larger portion of each of the sheaves to reduce the possibility of Slipping and wearing.

The drive motor 44 is mounted on top of a main supporting panel 48 of the scrubbing unit 20 by means of a suitable bracket 50 which preferably resiliently holds the motor 44 to urge it away from the driven motor pulley 38 so as to maintain the motor belt `40 in tension. All of the drive components for the scrubbing heads 28 are located below the supporting panel 48 except for the motor 44.

The scrubbing head sheaves 30 are rotatably mounted on hollow axles 52 by means of bearings 54, the axles 52 extending through and being supported by the support panel 48. Water is Supplied through the hollow axles 52 by suitable flexible hoses 56 which are connected to the cleaning fluid tank in the body 12 of the machine 10, the hoses 56 and their appropriate fittings -being enclosed in a suitable housing 57 (FIG. 2) on the panel 48.

A scrubbing tool 58 (FIG. 3) is removably attached to the sheave 30 and has a backing disc or member 59 including an upper plate 60 and a lower plate 62 held in spaced relationship by an annular, grooved ring 64 aixed to the plates by suitable screws 66. The upper and lower plates 60 and 62 have central openings 68 and 70 aligned with the hollow axle 52 so that water flowing through the axle 52 can pass through both of the plates 60 and 62. The water thereby flows centrally to a scrubbing sheet or scrubbing means 72 which is wrapped around the backing disc 59 and is attached to the grooved ring 64 by means of a spring or other suitable resilient band 74, a resilient pad 75 being located back of the sheet. Because the water is supplied centrally to the scrubbing tool 58, it ows out equally in all directions therefrom so t-hat the tool 58 can clean uniformly. Further, the Water will not hit and be thrown from the scrubbing tool 58 so that splashing is thereby maintained at a minimum.

The scrubbing tool 58 is attached to the sheave 30 by means of a pair of connecting pins 76 which have Shanks 78 axed to diametrically-opposed portions of the sheave 30 and enlarged heads 80 which are integral with the Shanks 78. The upper plate 60 is provided with diametrically-opposed, arcuate slots 82 (FIG. 4), the center of curvature of which lies at the center of the plate 60, the slots 82 having intermediate, enlarged portions 84 which receive the heads of the pins 76. The backing disc 59 is rotated after the heads `80 of the pins 76 are inserted through the enlarged openings 84 of the slots 82 so that the heads then are located under the end portions of the slots 82 which are only slightly larger than the Shanks 78 of the pins 76. The heads 80 then prevent separation of the backing disc 59 from the sheave 30. The heads 80 are urged against the lower side of the upper plate 60 by means of springs 86 located around the Shanks 78 so that the scrubbing tool 58 can be moved upwardly if the force of the springs 86 is overcome. Hence, the scrubbing tools 58 can move up and down or be rocked to conform with any uneven surface and provide maximum cleaning power. In practice, the springs 86 are compressed somewhat when the scrubbing heads 28 are in contact with the surface so that the pin heads 80 are slightly below the upper plate 60, as shown in FIG. 3. In this manner, if one of the tools 58 encounters a recess, it can move downwardly to remain in full contact with the recessed surface.

When the backing disc 59 is assembled with the sheave 30, the disc is rotated relative to the sheave 30 in a manner such that the Shanks 78 of the pins 76 move in the slots 82 opposite to the direction of rotation of the tool 58 so that the pins are urged to remain against the ends of the Slots 82 when the tool 58 is rotated. However, to further prevent the possibility of the pins 76 moving to the center of the slots 82 and enabling the heads 80 to pass through the enlarged portions 84, annular discs or washers 88 are located between the springs 86 and the pin heads 80 and bear against the upper surface of the upper plate 60 when the sheave 30 is engaged with the tool 58. Generally radially-extending ridges 90 (FIG. 5) are located centrally with respect to the enlarged portions 34 and extend outwardly therefrom. These ridges prevent the annular discs S8 from moving back toward the enlarged portions 84, thereby also preventing the pin heads 80 from moving back to the enlarged portions.

The scrubbing unit 20 must be raised occasionally dur ing operation, such as when moving over door sills, for example, and preferably is raised out of the way when not in use. Accordingly, in a preferred form of the invention a rear portion of the unit is pivotally supported on an axle 92 (FIG. 6) by means of flanges 94 of a rear projecting portion 96 of the unit 20. A lever 98 is attached to the rear portion 96 and extends beyond the rear end or" the body 12 to a foot pedal 10G. When the pedal 100 is depressed, the entire unit 20 is rotated around the axle 92 in a clockwise direction as shown in FIG. 6 so that all of the scrubbing heads 28 and the motor 44 are raised together. By raising the motor 44 and the drive mecha` nism with the scrubbing heads 28, a much simpler drive connection, namely the various sheaves and belts, can be employed than would otherwise be possible. The lever 98 extends through an opening 102 in a rear wall 104 of the body 12, the opening 102 having a lower notch 106 into which the lever 98 can be pushed when in its lower position. The unit 20 can then remain in the raised position until the lever 98 is released from the notch 106.

The main wheels 14 are also driven by the motor 44. For this purpose, the motor 44 has a second motor drive sheave 108 (FIG. 6) which is connected to a gear shaft sheave 110 by means of a belt 112, the sheave 110 being mounted on the lower end of a generally verticallydisposed gear shaft 114 (FIG. 8) extending through a gear housing 116. The shaft 114 has a worm 118 mounted thereon which meshes with a worm wheel keyed to a generally horizontally-disposed shaft 122. The shaft 122 is rotatably supported by the gear housing 116 which, in turn, is supported on the panel 48 by means of a bracket 124. The outer end of the horizontal shaft 122 is provided with a wheel drive sheave 126 which is connected with an axle sheave 128 by a belt 130, the sheave 128 being axed to the axle 92 for the wheels 14.

When the second motor sheave 108 is driven, it rotates the vertical shaft 114 and turns the worm 118, thereby rotating the worm wheel 120 and the shaft 122, along with the wheel drive sheave 126. The latter drives the axle sheave 128 and thus turns the wheels 14 to drive the scrubbing machine 1t). Since the axle sheave 128 lhas the same center of rotation as the pivot point for the unit 20, the sheave 126 remains the same distance from the sheave 128 regardless of the position of the unit 20. Thus, the unit 29 can be easily raised and lowered without affecting the drive mechanism for the wheels 14.

However, the motor 44 can be engaged with and disengaged from the wheels 14 by varying the tension on the belt 130 which can be accomplished simply by moving the wheel drive sheave 126 toward and away from the axle 128. For this purpose, the horizontal shaft 122 can be swung in a horizontal plane by making the gear housing 116 pivotable with respect to the support bracket 124. This can be accomplished through a pair of flanges 132 axed to the bracket 124, each ange having an annular Wall 134 cooperating with a circular projection 136 at the uppper or lower end of the gear housing 116. In this manner, the gear housing 116 can pivot about an d axis which is concentric with the vertically-disposed shaft 114 whereby the yhousing can rotate without affecting the meshing of the worm 118 and the worm wheel or gear 120. When the housing 116 is rotated in a clockwise direction, the sheave 126 moves away from the sheave 12S and maintains the belt 130 in tension. Oppositely, when the gear housing 116 is moved in a counterclockwise direction, the sheave 126 moves toward the sheave 128 and reduces the tension in the belt 130, thereby disengaging the motor from the wheels 14.

The gear housing 116 can be rotated by means of a pivot arm 13S extending therefrom to which a iirst connecting rod 14'@ is attached by a ball and socket connection 142. The rod 14d is loosely connected to au L.'- shaped link 144- which is suitably pivoted to the body 12 of the scrubbing machine 1% by a pivot 146. The L-shaped link 144 is then connected by a linir 143 to a shift lever 15G located near the handle 18 of the machine 1@ so as to be easily operated by the machine operator.

When the shift lever 15th is pushed toward the front of t 1e machine, the link 143 forces the L-shaped link 146 in zt clockwise direction, thereby pulling on the connecting rod 146 and moving the gear box 116 in a counterclockwise direction. This swings the drive wheel sheave 125 toward the axle sheave 128 and disconnects the drive for the wheels 14. When it is desired to drive the machine 1t?, the shift lever 15@ is pulled toward the rear which causes the L-shaped link 144 to move in a countercleckwise direction, thereby pushing on the connecting link 14d and moving the gear housing 116 in a clockwise direction. The drive wheel `sheave 126 is thereby moved away from the axle sheave 128, placing the belt 130 in tension and causing driving engagement between the sheaves 126 and 12S. This provides a simple, effective means for controlling the drive for the wheels 14 and yet does not interfere with pivoting of the unit 20. When the unit 2b is pivoted, and the gear housing 116 moves upwardly and downwardly to some extent around the axle 92, the movement is taken up by the connecting rod 1li@ with its ball and socket connection 142 in the arm 138.

A modified scrubbing tool 152 is shown in vertical cross section in FIG. 9. The scrubbing tool includes a modified backing disc or member 15d having an upper plate 156, which is quite similar to the upper plate 611 of the backing member and a lower, thick plate 15S which can be made of wood, such as plywood. The upper plate 156 is connected to the lower plate 158 through wood screws 16d which extend through Vspacing tubes 162 to hold the upper and lower plates in spaced relationship. `Both the upper plate 156 and the lower plate 158 have openings 16d and 166 which are aligned with the hollow axle 52 when connected to the sheave 3i). The cleaning liuid thereby iiows centrally to a scrubbing sheet or scrubbing means 168, the diameter of which is substantially equal to the diameter of the thick, lower plate 158, in this instance. The scrubbing sheet 16S also has a slit central portion which forms a pluraiity of tabs 170 which are turned upwardly into the central opening 166 in the plate 158. A rubber ring or grommet 172 is then snapped into the opening 166 to hold the sheet 168 adjacent the bottom of the backing member 154. The diameter of the rubber grommet 172 is preferably slightly larger than the diameter of the hole 166 to engage rmly the tabs 17u of the scrubbing sheet 1168. Although the grommet 172 holds the sheet 16S against the bottom of the backing member 154, so that the two can be lifted together, the backing member 154 actually drives or rotates the sheet 168 through a plurality of brous tufts 174 which project slightly from the lower surface of the thick plate 153 and barely penetrate the sheet 168. This provides mechanical engagement between the plate and the sheet, which is only slightly more than frictional engagement, so that the sheet 16S rotates with the plate 158.

The mounting arrangement of FiG. 9 has several ad- Vantages over the arrangement shown in FIG. 3. Less material is required for the sheet 168 than for the sheet 72 of FIG. 3 because the portion extending upwardly around the backing disc 59 is eliminated. Also, the scrubbing tools 152 can be placed closer together because no extra space has to be provided for the portion of the sheet extending around the backing disc. Because of this, the backing disc 154 can be made with a 4 diameter rather than the 3% diameter of the backing disc 59 for the same scrubbing unit 20. The unit 20 thereby has a more elective cleaning action because the overlap of the adjacent scrubbing heads is greater to decrease the possibility of streaking.

The scrubbing machine 1t)l and the scrubbing unit 20' can be used with other scrubbing means such as brushes in place of the scrubbing sheet 72 or 168. Accordingly, a modiied scrubbing tool 176 employing a brush is shown in FGS. 10 and 1l. The tool 176 includes a backing disc or member 178 having an upper plate 180 and a lower plate 182 to which are affixed bristles or scrubbing means 134. In this instance, the upper plate has arcuate slots 136 with enlarged portions 188 at one end rather than at intermediate portions, the reason for which will be discussed subsequently. The enlarged portions 18 receive the heads 80 of the pins 76 and the tool 176 is then rotated to move the heads 3d under the slots 186, as before. Ridges 189 are also formed in the plate 180 to engage the washers S3 and prevent the heads Sti from moving toward the enlarged portions 188. The plate 13d, in this instance, is mounted very close to the lower plate 182 and, therefore, openings 19t) are cut in the plate 132 to mal-:e room for the heads Si); The closer spacing of the plates enables the overall thickness of the tool 176 to be about the same as that of the tool 5S in spite of the long bristles 184.

The means for connecting the upper plate 180 to the lower plate 1%2 differs substantially from the connecting means of `FIGS. 3 and 9 because of the `following condition. As the bristles 1134 wear, the thickness of the tool 176 changes considerably as compared to the thickness of the tool 58 or 152, which will vary no more than about i in thickness even if the sheet 72 or 16S wears completely through. iIn contrast, the bristles 184 are in the order of 3/4" long and are effective until they wear to a length of only 1A, thus making a `1/z" change in the thickness of the tool 176. lt will be readily understood that as the bristles 184 wear, the scrubbing unit 29 moves more closely to the door so that the angle of the axle 52 (FIG. 3) varies in relation to the plane of the floor. Preferably, the scrubbing unit 2t) is designed so that the axle 52 moves between positions on opposite sides of a truly perpendicular position as the bristles wear.

When the axle 52 is in a slanted position with respect to the surface being cleaned, the scrubbing tool 178 will rotate in a plane which is not perpendicular to the axle 52. Since the sheave 30 rotates in a plane truly perpendicular to the axle 52, the plane of rotation of the scrubbing tool 176 and that of the sheave '3C-'l are not parallel. Consequently, the pins 76 tend to move up and down in the slots 1&6 during rotation of the tool 176 and greatly increase the wear of both the pins 76 and the plate 118).

To overcome this diliicuty, the plate 180 is connected to the lower plate 182 by means of only two screws 192 ('FlG. l0) rather than four screws, as` shown in FIG. 4. Further, the plates 181i' and `18,2 are spaced apant by resilient spacing rings 194 so that the plates 180 land 182 can readily rock or wobble with respect to one another about a line intersecting the two screws 192. At the same mime, the ends of the slots 186 in which the shaniks` 78 of Ithe pins 76 are held lie in a line perpendicular to the line through Ithe screws 192. The mutual perpendicularity of relative motion between the pins 76 and the upper plate 131B, and between the upper plate 180 and the lower plate 182 enables action to be achieved which is similar to that of a universal joint. Thus, when the line between the screws 192 is perpendicular to the direction of travel of the scrubbing machine 10, the plate 180 will remain parallel tothe plane of rotation of the Sheave 30 and the plate 182 will remain in a position parallel to the oor because `the screws 12 and the rubber spacers 194 enable the plates 180 and 182 to rock out of their parallel positions. Hence, the pins 76 remain in the same relative positions with respect to the plate 180 yas if the axle 52 were perpendicular to the surface being cleaned. When the tool 176 rotates 90 so that the line through the screws 192 is parallel to the direction of movement of the scrubbing machine 10, Ithe plates 189 and 182 will not pivot to any degree and will remain in parallel planes which are parallel to the surface; in this instance, the lack of perpendicular-ity between the plane of the plate 180 and the axle 52 is taken up merely by a slight pivoting or slanting movement of the pins 76 with respect 4to the slots 136. Thus, there is substantially no longitudinal movement of the pins 76 with respect to the plate 180 las would otherwise occur with the connections of FIGS. 3 and 9, particularly when a line through the pins 76 is parallel to the direction of movement of the scrubbing machine.

Because maximum effectiveness of the pivoting or universal action between the pins 76 and the plates 130 and 182 is achieved when a line through the pins 76 is perpendicular to the lline through the spacers 194 or the screws 192, the slots 186 are designed to be used only with a particular one of the scrubbing heads 28, depending upon the direction of rot-ation of the heads. Thus, the slots 186 and the enlarged portions 188 of the plate 180 of FIG. l0 'are designed for a scrubbing head 28 driven in a counterclockwise direction. Similarly, the enlarged portions 18S are located at the opposite ends of the slots 186 when the heads are rotated in the opposite direction. In each case, however, a line through the pins 76, when positioned in `the ends of the slots, is perpendicular to a line through the screws 192. Because all of the front scrubbing heads 28 rotate in one direction and all of the rear ones rotate in the opposite direction, the plates 180 can be marked either front or back so that the operator can easily assemble the scrubbing tools 176 with the proper sheaves 30.

Various modifications of the abovefdescribed embodiment ofthe invention will be apparent to those skilled in the art and it is to be understood that such modiiications can be made without departing from the scope ot the invention if they are within the spirit and tenor of the accompanying claims.

What I claim is:

l. A scrubbing machine comprising a main body, a pair of wheels and a wheel yaxle mounted under said body, a scrubbing unit under said body and mounted for pivotal movement with respect thereto, said scrubbing unit including a supporting panel, a plurality of verticallydisposed scrubbing tool axles supported by said panel, a scrubbing tool rotatably supported by each of said axles, a motor mounted on said scrubbing unit and movable therewith, means connecting said motor and said scrubbing tools to rotate said scrubbing tools with respect to said scrubbing tool axles, means extending rearwardly from said unit and attached thereto for pivotally raising said unit, means connecting said motor to said wheei axle to drive said wheels, and means controlled by an operator for rendering the latter connecting means inoperable.

2. A scrubbing machine comprising a main body, a pair of supporting wheels and a wheel axle mounted under an intermediate portion of said body, a scrubbing unit under said body and pivotally attached to said wheel axle, said scrubbing unit including a supporting panel, a plurality of vertical axles supported by said panel in staggered relationship and generally perpendicularly disposed to the direction of movement of thc machine, a scrubbing Atool rotatably supported by each of said axles, a motor mounted on said unit and movable therewith, belt and sheave means connecting said motor and said scrubbing tools for driving said tools, -with adjacent tools rotating in opposite directions, `a lever attached to said unit and extending rearwardly lthereof beyond said wheel axle, said lever being capable of being depressed by an operator to pivotally raise said unit, and means connecting said motor to said wheel axle to drive said wheels.

3. A scrubbing head for a scrubbing machine comprising a Ivertically-supported, hollow axle, a shcave, bearing means rotatably supporting said sheave on said axle, pins depending from said sheave and uniformly spaced therearound, said pins having enlarged heads at their lower ends, a spring around each of said pins, an annular disc through which each of said pins extends with the disc located between the spring and the head of the associated pin, a scrubbing tool backing member, said member including an upper and a lower plate and means to connect said plates in spaced relationship to one another, each of said plates having a central opening aligned with said axle, said axle terminating above the lower plate, means for supplying cleaning fluid to the upper end of said axle, the upper plate having an arcuate slot for each of said pins, the center of curvature of the arcs being at the ccnter of said upper plate, each of said slots having an enlarged portion to receive the Vhead of one of said pins, the main portion of each of said slots being slightly larger than the diameter of the associated pin, said upper plate having a ridge extending outwardly from the enlarged portion of each of said slots, said disc being located to one side of the associated ridge and urged against the upper surface of the upper plate by the spring when the head of the associated pin is inserted through the enlarged portion of the slot and the member is rotated relative to the pins, scrubbing means, and means attaching said scrubbing means to said backing member with at least a substantial portion of said scrubbing means bcing located below said lower plate.

4. A scrubbing head for a scrubbing machine comprising a vertically-supported axle, a drive sheave, bearing means rotatably supporting said drive sheavc on said axle, two pins depending from said sheave and diametrically opposed thereon, said pins having enlarged heads at their lower ends, a scrubbing tool driven by said sheave, said scrubbing tool including a backing member having an upper and a lower plate, the upper plate having an arcuate slot for each of said pins, means resiliently connecting said upper and said lower plates in spaced relationship, a line through said pins, when in ends of said slots, intersecting a line between said resilient connecting means and positioned generally perpendicular thereto, scrubbing means, and means attaching said scrubbing means to said backing member with at least a substantial portion of said scrubbing means being located below said lower plate.

5. A scrubbing head -for a scrubbing machine comprising a vertically-supported, hollow axle, a sheave, bearing means rotatably supporting said sheave on said axle, pins depending from said sheave and uniformly spaced therearound, said pins having enlarged heads at their lower ends, a spring around each of said pins, a scrubbing tool backing member including a plate having a central opening aligned with said axle, means for supplying cleaning iluid to the upper end of said axle, said plate having an arcuate slot for each of said pins, the center of curvature of the arcs being at the center of said plate, each of said slots having an enlarged portion to receive the head of the associated pin, the main portion of each of said slots being slightly larger than the diameter of the associated pin, said spring urging said plate downwardly away from said sheave when the head of said pin is engaged in the slot, scrubbing means, and means attaching said scrubbing means to said backing member with at least a substantial portion or" said scrubbing means being located below said member.

6. A scrubbing head for a scrubbing machine comprising a vertically-supported axle, a sheave, bearing means rotatably supporting said sheave on said axle, pins depending from said sheave and uniformly spaced thereon, said pins having enlarged heads at their lower ends, a spring around each of said pins, a scrubbing tool backing member including a plate, said plate having an arcuate slot for each of said pins, the center of curvature of the arcs being at the center of said plate, each or" said slots having an enlarged portion to receive the head of the associated pin, the main portion of each of said slots being slightly larger than the diameter of the associate-d pin, said spring urging said plate away from said sheave when the pin is engaged in its associated slot, scrubbing means, and means attaching said scrubbing means to said backing member.

7. A scrubbing head for a scrubbing machine comprising a vertically-supported, hollow axle, a sheave, bearing means rotatably supporting said `sheave on said axle, a scrubbing tool backing member, said backing member having a central opening, resilient means connecting said backing member directly to said sheave with the opening aligned with 4the lower end of said hollow axle, means for supplying a cleaning lluid to the upper end of said axle, scrubbing means, `and means attaching said scrubbing means to said backing member.

8. A scrubbing head according to claim 7 wherein said scrubbing means comprises a multiplicity of bristles.

9. A scrubbing head according to claim 7 wherein said scrubbing means comprises a scrubbing pad.

l0. ln a scrubbing machine, a body, a pair of wheels and a wheel axle supporting said body, a scrubbing unit below said body, a plurality of scrubbing heads rotatably mounted on said unit, a motor, means connecting said motor to said heads to rotate same, a gear housing, means pivotally mounting said gear housing on said machine, a generally vertical shaft rotatably supported by said housing and extending outwandly from at least one end of said housing, a first sheave attached to one end of said vertical shaft outside said housing, a second sheave connected `to said motor, belt means connecting said rst and second sheaves, Iwhereby said motor can rotate said vertical shaft, a worm on said vertical shaft within said housing, a generally horizontally-disposed shaft in said housing and extending outwardly from one side thereof, a 'wohin wheel attached `to said generally horizontallydisposed shaft within said housing .and meshing with said worm, a wheel drive sheave on said horizontally-disposed shat and spaced from said housing, an axle sheave on said wheel axle, second belt means connecting said drive and Lxle sheaves, link means connected to `said housing and extending to an opera-tors position spaced therefrom for rotating said housing to swing said horizontally-disposed shaft in a horizontal plane, whereby said drive sheave can be moved toward and away from said axle sheave to vary the tension on said second belt means and thereby enable an operator to drive said wheels as n desired.

ll. in a scrubbing machine, a body, a pair of wheels and a wh el axle supporting said body, a scrubbing unit below said body, a plurality of scrubbing heads rotatably mounted on said unit, a motor, means connecting said motor to said scrubbing head Ito rotate same, a gear housing, means pivotal-ly mounting said gear housing on said unit, a generally vertical shaft rotatably supported by said housing and extending therethrough, means connecting said :motor and said vertical shaft to rotate the same, a iirst gear on said vertical shaft within said housing, a generally horizontally-disposed shaft in said hou-sing and extending outwardly :from one side thereof, a second gear on said horizontal shaft within said housing and meshing with the hrst gear, la dni-ve sheave on said horizontal shaft and spaced from said housing, an axle sheave on said wheel axle, a belt connecting said drive sheave and said axle sheave, link means connected to said housing and extending to an operators position spaced therefrom for rotating said housing to swing said horizontal shaft in a horizontal plane whereby `said drive sheave can be moved toward and away from said axle sheave to vary the tens-ion on said belt and thereby enable an operator to drive said wheels as desired.

References Cited in the file of this patent UNITED STATES PATENTS 2,317,843 Backlund Apr. 27, 1943 2,591,093 Okun Apr. 1, 1952 2,893,037 Strong lully 7, 1959 2,969,557 Petersen Jan. 31, l96l 

1. A SCRUBBING MACHINE COMPRISING A MAIN BODY, A PAIR OF WHEELS AND A WHEEL AXLE MOUNTED UNDER SAID BODY, A SCRUBBING UNIT UNDER SAID BODY AND MOUNTED FOR PIVOTAL MOVEMENT WITH RESPECT THERETO, SAID SCRUBBING UNIT INCLUDING A SUPPORTING PANEL, A PLURALITY OF VERTICALLYDISPOSED SCRUBBING TOOL AXLES SUPPORTED BY SAID PANEL, A SCRUBBING TOOL ROTABLY SUPPORTED BY EACH OF SAID AXLES, A MOTOR MOUNTED ON SAID SCRUBBING UNIT AND MOVABLE THEREWITH, MEANS CONNECTING SAID MOTOR AND SAID SCRUBBING TOOLS TO ROTATE SAID SCRUBBING TOOLS WITH RESPECT TO SAID SCRUBBING TOOL AXLES, MEANS EXTENDING REARWARDLY FROM SAID UNIT AND ATTACHED THERETO FOR PIVOTALLY RAISING SAID UNIT, MEANS CONNECTING SAID MOTOR TO SAID WHEEL AXLE TO DRIVE SAID WHEELS, AND MEANS CONTROLLED BY AN OPERATOR FOR RENDERING THE LATTER CONNECTING MEANS INOPERABLE. 